Draft control



May 3,1927.

C. M. NORBERG DRAFT CONTROL Filed July 17, 1926 Patented May 3, 1927.

UNITED STATES I 1,627,194 PATENT ornca.

CLIFFORD M. NOBBERG, F MASPETH, NEW YORK.

v DRAFT CONTROL.

Application filed July 17, 1926. Serial no. 123,104.

The invention relates to improvements in draft control. The invention comprises method and means for securing an arbitrary selection between natural and artificial drafts or any desired combination of same.

Said selection and combination being adapted for automatic control.

The invention is especially adapted to fuel combustion. The invention maybe effected by a draft door or damper in combination with a blower, or artificial draft booster and a controlling means for the blower in adj ustable relation'with the draft door or damper.

The principal object is to provide method and means whereby the arbitrary selection between natural and artificial drafts can easily be set to obtain any desired amount of draft needed to produce the best results in the combustion of fuel.

Another object of the invention is to leave the motor circuit open when the damper door is closed, thus stopping the artificial draft mechanism when it is useless to have it in operation.

merely by way of example, means for effeeling the invention V Fig. 1 is a part elevation and part vertical section.

Fig. 2 is a detail in partelevation and part section, on an enlarged scale.

Fig. 3' is a plan view of the same.

Similar numerals refer to similar parts throughout the several. views.

The chambered casing or formatlon 5 is adapted to be secured to the usual lower or ash pit door 6, of the furnace, after removing the gravity damper usually connected therewith. The adapter portion 7 has an inclined margin 8 conforming to the inclincd margin of the damper opening of the furnace door. The opposite side of the chambered body 5 is provided with a similar gravity damper 9 to take the place of the one removed fromthe furnace door 6. W'ithin the casing or formation 5 isv suitably mounted the motor 10 and fan 11 adapted 'to induce a current of air through the furlnace door 6.

The damper 9 is hinged at 12 and 1s preferably provided with the lug 13 for connection by chain 14 to the usual thermostat or pressure controlling device, not shown.

Upon the inner side of damper 9 1s secured the bracket 15, to which is pivoted, as lit 21, the element 16 having the operating Referring to the drawings which illustrate,

nace door.

handle 17. The element 16 is provided with a series of recesses 18, adapted to cooperate with the detent 19, controlled by spring 20. The detent and spring being associated with the bracket 15. Element 16 carries the switch casing 22. This casing is provided with a mercury switch comprising the glass tube 23 and the electrodes 24 and 25, said electrodes being connected to the wires 26 and 27 of the motor circuit.

In operation; when the damper 9 is in closed position, the switch casing 22 is supported thereby so that the mercury .tube will be slightly inclined to the horizontal, as

shown in Fig. 2. hen the lower end of the damper 9 is lifted to open same the casing 22 and tube 23 will be correspondingly moved, so that their angular position wlth respect to the horizontal, will be changed; that is the right hand end of the, tube 23 will be lowered and the left hand end elevated. This will cause the mercury in the tube to flow toward the electrode 25, and when the movement is sufficient, the mercury will establish electrical connection between said electrodes and thus close the motor circuit. The amount of opening movement of" damper 9, necessary to close the motor cir-' cuit, will depend upon the adjusted position of the switch casing 22 when the damper is closed. i

It will thus be seen that by the arbitrary adjustment of casing 22 by means of handle 17, the amount of damper opening to cause the closing of the motor circuit, may be secured at will. That is to say, the parts may be so adjusted that the damper may be partly open for natural draft, without closing the motor circuit; but upon a predetermined opening of the damper, the motor circuit will be closed and an induced current of air will be forced through the fur- By the proper adjustment the casing 22, a very slight opening or a comparatively large opening of the damper will be required for closing the motor circuit. In this way the natural draft alone may be permitted to function for a predetermined opening of the damper.

Another feature of this device is its adaptability to special controls, such as thermostatic or pressure controlled heating systems. Inasmuch as these systems usually operate the dampers of a furnace to whic they are attached, they may at the same time control the artificial draft producer.

.the parts in position of adjustment, until the d The cooperating detent and recess means' between bracket 15 and element 16 will hold again arbitrarily operated.

While I have illustrated and described a preferred embodiment of my invention, it will be understood that other means may be devised to the same end, with satisfactory results, without departing from the'principle of the invention; the-essential features of which are a movable damper and controlling switch associated therewith and operating relatively with the movement o'f amper. I What I claim is 1. The combination of a chambered format-ion," an electrically driven blower therefor controlling the blower, pivotally supported upon the damper and operating rela tively with the movement of the damper, and means for adjusting the pivotal relationship of the switch upon the damper.

eaner 3. The combination of a casing, an electrically driven blower therein, a damper opcrating by gravity normally closing the inlet to the, casing, a gravity actuated circuit. controlling sw tch supported upon and movable with the damper:

able with the damper, and means for arbitrarily adjusting the initial position of the switch upon the damper.

5. The combination of a casing, an electrically driven blower therein, a damper operating by gravity normally closing the in let to the casing, a gravity actuated circuit controlling switch pivotally connected to the damper and manually operated means for adjusting the pivotal relationship be tween the damper and switch.

6. The combination of a casing, an electrically driven blower therein, a damper operating by gravity normally closing the inlet to the casing, a gravity actuated circuit controlling switch pivotally connected to the damper, manually o erated means for adjusting the pivotal re ationship between the damper and switch, and recess and detent means for maintaining said adjustment.

CLIFFORD M. NORBERG. 

